Secondary amines of 3, 3 bis (p-amino-phenyl) phthalide



Patented June 21, 1949 7 UNITED STATES PATENT OFFICE SECONDARY AMINES OF 3,3 BIS (P-AMINO- PHENYL) PHTHALIDE Clyde S. Adams, Yellow Springs, Ohio, assignor to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland No Drawing. Application April 12, 1945, Serial No. 588,077

5 Claims. (Cl. 260344.6)

This invention relates to normally colorless Class V, the mono-valent aromatic hydrocarbon substances which assume a color under certain radicals, exemplified by the phenyl radical conditions, and particularly pertains to the sec- (CsHs-). ondary amines of 3,3 bis (p-aminophenyl) Class VI, the mono-valent aromatic hydrocarbon phthalide, having the general structure 5 radicals having a substituent for one or more of the hydrogen atoms, as exemplified by the H H sulphophenyl radical (HSO3C6H4) Class VII, the mono-valent heterocyclic radicals,

as exemplified by the pyridyl radical (C5I-I4N) 10 Class VIII, the mono-valent heterocyclic radicals c having a substituent fOr one or more of the hydrogen atoms, as exemplified by the methyll pyridyl radical (CH3C5I-I3N).

The compounds of these classes are colorless or 15 practically colorless in their normal state, but each may be affected so as to cause it to assume a strong blue color by reason of a change in its Where R is a mOflO-V Organic radical, and light-absorbing characteristics. One Way of in which NI-IR is a Se y aminecausing the color to app-ear is to adsorb the com- The O ganic rad Which R represents may 90 pound on a polar substance. Another Way of be ta en f o y 6 0f the following classes, causing the color to appear is to treat the comeach identified by one or more typical reprE- pound with a Weak acid. sentatives: By polar substance is meant a compound Class I, the mono-valent aliphatic hydrocarbon Whose 9 elefztricany asymmetric radicals exemplified by the methyl radical Clay, various silicates, silicon dioxide, magnesium carbonate, calcium carbonate, aluminum lass II, the monowalent aliphatic hydrocarbon phosphate, zinc sulphide, aluminum oxide, calradicals having a substituent for one more cium chlorlde, calcium fluoride, and calcium sulhydrogen atoms phate are representative polar substances of rela- A. As exemplified by the chloromethyl mew d0 tively hlgh effectiveness in connection with the cal (CH2C1 novel co1or-reactant compounds. B AS exemplified by the benzy radical {among the Weak acids may be mentioned acetic (C6H5CH2 or ac d and tartaric acid, although diluted stronger C. As exemplified by a sulphobenzyl radi- We aclds W111 9',

cal such as (HSO3CBH4CHZ The stability of the new compounds in the Class III, the mono-Valent alicyclic hydrocarbon leuco or 601911855 state gives: h a Wide l of radicals-y exemplified by the cyclopropyl usefulness in the art of printing or writing, cal wherein the color-reactant compound is placed in juxtaposition, but not in adsorption contact, with a polar substance to form a coating for record material. Upon the juxtaposed substances being brought into intimate contact Class IV, the mono-valent alicyclic hydrocarbon locally, by impact c b g pressures, adsorpradicals having a substituent for one or more tion takes plate, p uc a Strong co o Such of th hydrogen atoms, xem lified by a Chloro- 5 coatings for record material made of the colorcyclopropy] radical such as reactant compounds which are the subject of this invention are stable because the color-reactant compounds are stable to normal environ- 01 CH0 mental conditions in the leuco state and, on the 50 other hand, will persist in the colored state as long as the color-inducing cause persists. Reference is made to the United States patent application Serial No. 784,938, filed November 8, 1947, as a continuation of United States patent application Serial Number 520,573, filed January 31, 1944, by Barrett K. Green, and now abandoned for a complete description of an impactresponsive record material coating of the kind mentioned.

Therefore, among the objects of the invention is to provide a new type of compound comprising the secondary amines of 3,3 bis (p-aminophenyl) phthalide.

Another object of the invention is to provide a new type of compound the member compounds of which are normally colorless and stable but which may be made to assume a color in the presence of a polar substance, in the presence of an acid substance or in the presence. of other environmental conditions capable of altering their light-absorbing characteristics.

Another object of the invention is' to provide methods for making the new type of substances.

Examples will be given of the process of making several specific ones of these new compounds, from known materials, in a manner which will serve to show how all of the various types of com pounds included within the invention may be produced.

Class I compounds may be made by following the general method of making the specific compound 3,3 bis (p-methylam-inophenyl) phthalide having the structure Fifty grams of anhydrous aluminum chloride are dissolved in 250 milliliters of dry nitrobenzene. To the solution are added 2.0 grams of 3,3 dichlorophthalide and 23 grams of N,N dimethyl N,l l' diphenyl urea, and the mixture is allowed to stand at room temperature for about an hour.

The resultant solution is then heated on a steam bath for approximately an hour and thereafter poured onto 1,000 grams of cracked ice which has been acidified with '75 milliliters of hydrochloric acid of approximately 1.18 specific gravity. The resultant mixture is then made up to two liters with water and is steam-distilled to remove most of the nitrobenzene. The residual steam-distilled mixture is cooled and the water is filtered therefrom. The remaining solid condensate mass is then dried and pulverized. 300 milliliters of diethyl ether are added to the pulverized solid mass to extract the last traces of nitrobenzene. After standing for several hours at room temperature, the diethyl ether is. decanted, and the solid is airdried, leaving the intermediate condensation product.

Ten grams of the intermediate condensation product are air-dried, powdered, and introduced into a glass pressure tube of about 160 milliliters capacity, and milliliters of hydrochloric acid of approximately 1.18 specific gravity are added. The tube is then sealed and heated in a bomb furnace for five hours at 140 degrees to 150 degrees centigrade in order to hydrolize the conden- '4 sation product. The tube is cooled and opened, and the contents is transferred to a beaker, where it is diluted with milliliters of water and boiled with sufiicient activated charcoal to decolorize it. The decolorized mixture is then suction-filtered, and the filtrate is cooled. and made slightly alkaline with ammonium hydroxide, which causes a precipitation of the final product in crude form. The precipitate is filtered out and washed with water. Next, the washed precipitate is recrystallized by the use. of hot 95% ethyl alcohol, giving the final product, 3,3- bis (p-methylaminophenyl) phthalide.

As another example of class I compounds, the process: of making, the ethyl type will be described, which has the structure NC 2H5 and which is named 3,3 bis (p-ethylaminophenyl) phthalide.

Fifty grams of anhydrous aluminum chloride are dissolved in 250 milliliters of dry nitrobenzene. To this solution are added 20 grams of 3,3 dichlorophthalid-e and 23 grams. of N,N' diethyl N,N' diphenyl urea, and the mixture is allowed to stand at room temperature for about two hours. The resultant solution is then heated on a steam bath for an hour and afterwards is poured onto 1,000 grams of cracked ice which has been acidified with 75 millilitersof hydrochloric acid of approximately 1.18 specific gravity. The resultant mixture is then made up-to two liters with water and is steam-distilled to remove most of the nitrobenzene. The residual steam-distilled mixture is cooled, and the water isfi-ltered therefrom. The

- remaining solid mass. is then air-dried and pulverized. 3.00 m-illiliters ofdiethyl ether are added to the pulverized solid mass to extract the last traces of nitrobenzene. After standing at room temperature for several hours, the diethyl ether is decanted and the solid is air-dried, leaving an intermediate condensation product.

Ten. grams, of the intermediate condensation product are air-dried, powdered, and introduced into a glass pressure tube of about. 160 milliliters capacity, and 25 milliliters of hydrochloric acid of approximately 1.18 specific gravity are added. The tube is then sealed and heated in a bomb furnace for five hours at between degrees and degrees centigrade in order tohydrolize the condensation product. The tube is cooled and opened, and the contentsv is transferred to a beaker, where. it is diluted with 150 milliliters of water and boiled with sufiicient activated charcoal to decolorize it. The decolorized mixture is then suction-filtered, and the filtrate is cooled and made slightly alkaline with ammonium hydroxide, which causes the precipitation of the final product in crude form, The precipitate is filtered out and washed with water. Next, the Washed precipitate is recrystallized by the use of hot 95% ethyl alcohol, giving the final product, 3,3 bis (p-ethylaminophenyl) phthalide.

The other classes of compounds noted under the headings II, III, IV, V, VI, VII, and VIII may be made in a similar manner by selection of a proper compound of the N,N' diphenyl urea class having the structural formula In commercial practice, the material used may be o-phthaloyl chloride in equilibrium association with 3,3 dichlorophthalide. The o-phthaloyl chloride present in the commercial product is converted in the presence of aluminum chloride into 3,3 dichlorophthalide, in which form it condenses with the selected substituted diphenyl urea compound. The following structural relationship exists between the o-phthaloyl chloride and the 3,3 dichlorophthalide:

The Eastman compound phthalyl chloride is of the type containing the o-phthaloyl chloride and 3,3 dichlorophthalide in equilibrium.

While the forms of several of the compounds have been specifically described, it is to be understood that the invention is not to be limited to such compounds, as such are given as examples of members of the class, and means has been specified whereby other similar compounds in the same classes may be formed.

What is claimed is:

1. The compound of the formula H RN l IR For instance, in making 3,3

6 in which NI-IR is a secondary amine and R is a mono-valent hydrocarbon radical containing not more than 6 carbon atoms when it is a straight chain, not more than 5 carbon atoms when it is a branched chain, and not more than 9 carbon atoms when it contains a cyclic group.

2. The compound of the formula where R is a mono-valent aliphatic hydrocarbon radical containing not more'than 6 carbon atoms when it is a straight chain and not more than 5 carbon atoms if it is a branched chain.

3. The compound of the formula where R is a mono-valent alicyclic hydrocarbon radical containing not more than 5 carbon atoms.

4. The compound of the formula I I RN where R. is a mono-valent aromatic hydrocarbon radical containing not more than 6 carbon atoms.

5. The secondary amine 3,3 bis (p-methylaminophenyl) phthalide having the structure CLYDE S. ADAMS.

REFERENCES CITED The following referenlces are of record in the file of this patent:

Chemical Abstracts, 32, 1938, page 532, citing Schwarzenback et al., I-Iev. Chem. Acta 20, pages 1253-60 (1937).

Chemical Abstracts, 32, 1938, page 2106, citing Schwarzenback et al., Helv. Chem. Acta 20 (1937), pages 15911600. 

